Composition for ferroelectric thin film formation, ferroelectric thin film and liquid-jet head

ABSTRACT

A composition for ferroelectric thin film formation, comprising at least a colloidal solution containing metals serving as materials constituting a ferroelectric thin film, the colloidal solution having an average colloidal particle diameter of 1 to 100 nm, and obtaining a particle size distribution having two or more peaks; a ferroelectric thin film formed from the composition for ferroelectric thin film formation, and a liquid-jet head equipped with a piezoelectric element having the ferroelectric thin film.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is continuation of application Ser. No. 12/165,591 filed Jun. 30,2008, which is a divisional of application Ser. No. 11/227,158 filedSep. 16, 2005. Priority is claimed from JPA 2004-272094 filed Sep. 17,2004 and also from JPA 2005-004357 filed Jan. 11, 2005. The entiredisclosures of the above-identified applications and priority documentsare hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a composition for ferroelectric thin filmformation for use in forming a ferroelectric thin film, and also to aferroelectric thin film, and a liquid-jet head.

2. Description of the Related Art

A ferroelectric thin film containing a crystal, typified by leadzirconate titanate (PZT), has spontaneous polarization, a highdielectric constant, an electro-optic effect, a piezoelectric effect,and a pyroelectric effect, and thus finds application in the developmentof a wide variety of devices such as piezoelectric elements. As methodsfor forming such a ferroelectric thin film, the MOD method, the sol-gelprocess, CVD (chemical vapor deposition), and sputtering, for example,are known (e.g., see Japanese Patent Application Laid-Open No.2000-119022, “Prior Art”). A ferroelectric thin film is formed, forexample, by coating a composition for ferroelectric thin film formation(a colloidal solution) on a subject material, then drying and firing thecoating.

It is generally preferred that the ferroelectric thin film be a densefilm. In recent years, a demand for such a dense film has been growinggradually. The composition for ferroelectric thin film formation, whichis used to form a ferroelectric thin film, shows a tendency towardrelatively low storage stability. The ferroelectric thin film is usedfor a piezoelectric element, etc., as mentioned above. If its filmquality is poor, the piezoelectric characteristics of the piezoelectricelement having the ferroelectric thin film fluctuate. In a liquid-jethead having the piezoelectric element as a piezoelectric actuator,moreover, such fluctuations in the piezoelectric characteristics of thepiezoelectric element may cause variations in liquid ejectioncharacteristics.

SUMMARY OF THE INVENTION

The present invention has been accomplished in the light of theabove-described circumstances. It is an object of the invention toprovide a composition for ferroelectric thin film formation, which canform a dense film and has excellent storage stability, and to provide aferroelectric thin film, and a liquid-jet head.

A first aspect of the present invention for attaining the above objectis a composition for ferroelectric thin film formation, comprising atleast a colloidal solution containing metals serving as materialsconstituting a ferroelectric thin film, the colloidal solution having anaverage colloidal particle diameter of 1 to 100 nm, and obtaining aparticle size distribution having two or more peaks.

In the first aspect, a composition for ferroelectric thin filmformation, which can form a dense film and has good storage stability,can be achieved.

A second aspect of the present invention is the composition forferroelectric thin film formation according to the first aspect,characterized in that the average colloidal particle diameter is 1 to 30nm.

In the second aspect, a composition for ferroelectric thin filmformation, which can form a dense film more reliably and has betterstorage stability, can be achieved.

A third aspect of the present invention is the composition forferroelectric thin film formation according to the first or secondaspect, comprising the colloidal solution containing a complex having,as a nucleus, at least one of the metals serving as the materialsconstituting the ferroelectric thin film.

In the third aspect, a composition for ferroelectric thin filmformation, which contains a complex showing at least one peak in aparticle size distribution, enables a dense film to be formed, andexcellent storage stability to be achieved.

A fourth aspect of the present invention is the composition forferroelectric thin film formation according to any one of the first tothird aspects, comprising the colloidal solution containing a clustercomplex comprising a cluster of two or more complexes, each of thecomplexes having, as a nucleus, at least one of the metals serving asthe materials constituting the ferroelectric thin film.

In the fourth aspect, a composition for ferroelectric thin filmformation, which contains a cluster complex showing at least one peak ina particle size distribution, enables a dense film to be formed, andexcellent storage stability to be achieved.

A fifth aspect of the present invention is the composition forferroelectric thin film formation according to any one of the first tofourth aspects, comprising the colloidal solution containing a colloidalagglomerate comprising an agglomerate of complexes, each of thecomplexes having, as a nucleus, at least one of the metals serving asthe materials constituting the ferroelectric thin film.

In the fifth aspect, a composition for ferroelectric thin filmformation, which contains a colloidal agglomerate showing at least onepeak in a particle size distribution, enables a dense film to be formed,and excellent storage stability to be achieved.

A sixth aspect of the present invention is the composition forferroelectric thin film formation according to any one of the first tofifth aspects, characterized in that the metals serving as the materialsconstituting the ferroelectric thin film include at least Pb, Zr and Ti.

In the sixth aspect, a composition for ferroelectric thin filmformation, which can form a PZT film dense in terms of film quality andhas excellent storage stability, can be achieved.

A seventh aspect of the present invention is the composition forferroelectric thin film formation according to the sixth aspect,characterized in that the metals serving as the materials constitutingthe ferroelectric thin film are Pb, Zr and Ti, and the colloidalsolution contains colloidal particles comprising lead acetate, colloidalparticles comprising lead acetate and zirconium acetylacetonatestabilized by water molecules, and colloidal particles comprisingtitanium alkoxides and lead acetate chelate-stabilized by amines.

In the seventh aspect, a composition for ferroelectric thin filmformation, which contains colloidal particles comprising predeterminedcompounds, makes it possible to realize a composition for ferroelectricthin film formation which can form a PZT film dense in terms of filmquality and which has excellent storage stability.

An eighth aspect of the present invention is the composition forferroelectric thin film formation according to the seventh aspect,characterized in that the average colloidal particle diameter of thecolloidal particles comprising lead acetate is 1 to 6 nm, the averagecolloidal particle diameter of the colloidal particles comprising leadacetate and zirconium acetylacetonate stabilized by water molecules is 1to 10 nm, and the average colloidal particle diameter of the colloidalparticles comprising titanium alkoxides and lead acetatechelate-stabilized by amines is 3 to 50 nm.

In the eighth aspect, a composition for ferroelectric thin filmformation, which contains colloidal particles comprising predeterminedcompounds and having predetermined average colloidal particle diameters,makes it possible to realize a composition for ferroelectric thin filmformation which can form a PZT film dense in terms of film quality andwhich has excellent storage stability.

A ninth aspect of the present invention is the composition forferroelectric thin film formation according to the seventh or eighthaspect, characterized in that the colloidal particles comprising leadacetate, the colloidal particles comprising lead acetate and zirconiumacetylacetonate stabilized by water molecules, and the colloidalparticles comprising titanium alkoxides and lead acetatechelate-stabilized by amines have the average colloidal particlediameter in increasing order.

In the ninth aspect, a composition for ferroelectric thin filmformation, which contains colloidal particles comprising predeterminedcompounds and having predetermined average colloidal particle diameters,makes it possible to realize a composition for ferroelectric thin filmformation which can form a PZT film dense in terms of film quality andwhich has excellent storage stability.

A tenth aspect of the present invention is a ferroelectric thin filmformed from the composition for ferroelectric thin film formationaccording to any one of the first to ninth aspects.

In the tenth aspect, a ferroelectric thin film having stablepiezoelectric characteristics can be achieved.

An eleventh aspect of the present invention is a liquid-jet head whichis equipped with a piezoelectric element having the ferroelectric thinfilm according to the tenth aspect, as a piezoelectric actuator forjetting a liquid.

In the eleventh aspect, a liquid-jet head having stable liquid ejectioncharacteristics and having high reliability can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptionsin conjunction with the accompanying drawings.

FIG. 1 is a graph showing colloidal particle size distributions.

FIG. 2 is a graph showing colloidal particle size distributions.

FIG. 3 is an exploded perspective view showing the outline of arecording head according to Embodiment 2 of the present invention.

FIGS. 4A and 4B are, respectively, a plan view of the recording headaccording to Embodiment 2 of the present invention, and a sectional viewtaken along line A-A′ in the plan view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail based on theembodiments offered below.

Embodiment 1

The composition for ferroelectric thin film formation according to thepresent invention is a colloidal solution (sol) for use in forming aferroelectric thin film. Concretely, this composition comprises acolloidal solution containing metallic materials (for example,organometallic compounds) which become the materials constituting theferroelectric thin film. The colloidal solution has an average colloidalparticle diameter of 1 to 100 nm, and has the property of obtaining aparticle size distribution having two or more peaks.

The composition for ferroelectric thin film formation according to thepresent invention comprises a colloidal solution containing a complexhaving, as a nucleus, at least one of the metals which become thematerials constituting the ferroelectric thin film; a cluster complexcomprising a cluster of two or more of the complexes; or a colloidalagglomerate comprising an agglomerate of these complexes. Examples ofthe complex are those in which the nucleus is a metal becoming thematerial constituting the ferroelectric thin film, and a ligand, forexample, derived from alcohols, acetic acid, acethylacetonato, water(OH) or amines, is bound to the nucleus.

The above-mentioned composition for ferroelectric thin film formation,concretely, comprises a colloidal solution which has an averagecolloidal particle diameter, by the dynamic light scattering method, of1 to 100 nm, preferably, 1 to 30 nm, and which obtains a particle sizedistribution having two or more peaks ascribed to these colloidalparticles. Such a composition for ferroelectric thin film formation iscoated on the subject material, dried and fired, whereby a ferroelectricthin film dense in terms of film quality can be formed. The compositionfor ferroelectric thin film formation also shows excellent storagestability.

If, for example, the metals contained in the composition forferroelectric thin film formation are Pb, Zr and Ti, namely, in the caseof a colloidal solution of a composition for PZT thin film formation,there are contained various colloidal particles, concretely, colloidalparticles containing Pb alone (e.g., colloidal particles comprising leadacetate), colloidal particles containing Pb and Zr (e.g., colloidalparticles comprising lead acetate and zirconium acetylacetonatestabilized by water molecules), and colloidal particles containing Pband Ti (e.g., colloidal particles comprising titanium alkoxides and leadacetate chelate-stabilized by amines).

The composition for ferroelectric thin film formation (colloidalsolution) containing colloidal particles containing Pb alone, colloidalparticles containing Pb and Zr, and colloidal particles containing Pband Ti shows excellent storage stability. By forming a PZT thin filmfrom this composition for PZT thin film formation, the resulting PZTthin film is dense in terms of film quality.

In this composition for PZT thin film formation, moreover, the averagecolloidal particle diameters of the various colloidal particlescontained in the solution are set at values in predetermined ranges. Byso doing, a PZT thin film dense in terms of film quality can be formedmore reliably, and the storage stability of the composition for PZT thinfilm formation can be further enhanced.

For example, the average colloidal particle diameter of the colloidalparticles comprising lead acetate is preferably 1 to 6 nm, the averagecolloidal particle diameter of the colloidal particles comprising leadacetate and zirconium acetylacetonate stabilized by water molecules ispreferably 1 to 10 nm, and the average colloidal particle diameter ofthe colloidal particles comprising titanium alkoxides and lead acetatechelate-stabilized by amines is preferably 3 to 50 nm.

Particularly in the respective colloidal particles contained in thecomposition for PZT thin film formation, the colloidal particlescomprising lead acetate, the colloidal particles comprising lead acetateand zirconium acetylacetonate stabilized by water molecules, and thecolloidal particles comprising titanium alkoxides and lead acetatechelate-stabilized by amines have the average colloidal particlediameter in increasing order. By incorporating these colloidalparticles, a PZT thin film can be formed more reliably, and the storagestability of the composition for PZT thin film formation can be furtherenhanced.

There were prepared respective colloidal solutions (Pb; Sample 1, Zr;Sample 2, Ti; Sample 3) obtained by individually dispersing metallicmaterials constituting a PZT thin film as a ferroelectric thin film,concretely, organometallic compounds containing Pb, Zr and Ti (leadacetate trihydrate (Pb(CH3COO)2·3H2O), zirconium acetylacetonate(Zr(CH3COCHCOCH3)4), and titanium tetraisopropoxide (Ti((CH3)2CHO)4)),and a colloidal solution (Sample 4) obtained by simultaneouslydispersing the respective organometallic compounds containing Pb, Zr andTi.

These colloidal solutions, named Samples 1 to 4, were measured for thecolloidal particle size distribution including the particle size (nm)based on scattering intensity determined by the dynamic light scatteringmethod, which is give as abscissas, and the intensity (%), which isgiven as ordinates, by use of a photon correlation spectroscope (PCS)“ZETA SIZER NANO, a product of MALVERN”. The results are shown inFIG. 1. Separately, colloidal solutions were prepared by removing Pb(Sample 5), removing Zr (Sample 6), or removing Ti (Sample 7), from thecolloidal solution of the same composition as Sample 4. These Samples 5to 7 were also measured for the particle size and the colloidal particlesize distribution under the same conditions as for the above-mentionedSamples 1 to 4. The results are shown in FIG. 2.

In the colloidal particle size distributions shown in FIG. 1, a peakindicating the colloidal particles contained in the colloidal solutionas Sample 1 having Pb dispersed alone therein was present in thevicinity of about 3 nm, a peak indicating the colloidal particlescontained in the colloidal solution as Sample 2 having Zr dispersedalone therein was present near about 2 nm, and a peak indicating thecolloidal particles contained in the colloidal solution as Sample 3having Ti dispersed alone therein was present in the vicinity of about 2nm. On the other hand, a total of 2 peaks were present for the colloidalsolution as Sample 4, i.e., a peak with an intensity of about 5%existent close to about 3 nm, and a peak with an intensity of about 10%present near about 10 nm, concretely, the two peaks representing thecolloidal particles with a small particle size and the colloidalparticles with an intermediate particle size.

In the colloidal particle size distributions shown in FIG. 2, thecolloidal solution as Sample 5 containing Zr and Ti showed the presenceof a single peak in the vicinity of about 2 nm. For Sample 6 containingPb and Ti, a single peak was present near about 10 to 20 nm. Further, inconnection with Sample 7 containing Pb and Zr, a single peak was presentnear about 3 nm.

A comparison between the colloidal particle size distributions in FIG. 1and the colloidal particle size distributions in FIG. 2 showed that thepeak representing the small particle size of the colloidal solution asSample 4 (composition for PZT thin film formation), the peak of thecolloidal solution as Sample 1, and the peak of the colloidal solutionof Sample 7 were present at positions close to each other, and that thepeak representing the intermediate particle size of Sample 4 (thecolloidal particles corresponding to the peak present near about 10 nm),and the peak of the colloidal solution as Sample 6 were present atpositions close to each other. Based on these findings, it became clearthat the metal combination of Pb and Zr and that of Pb and Ti showed astrong interaction between the metals, while the metal combination of Zrand Ti showed little interaction between the metals.

In the light of the above results, the colloidal particles with a smallparticle size (2 to 4 nm) in the composition for PZT thin film formation(Sample 4) were either the colloidal particles comprising lead acetate,or the colloidal particles comprising lead acetate and zirconiumacetylacetonate stabilized by water molecules, and the colloidalparticles with an intermediate particle size (9 to 20 nm) in thiscomposition were the colloidal particles comprising titanium alkoxidesand lead acetate chelate-stabilized by amines. In other words, thecomposition for PZT thin film formation, as Sample 4, is mainly composedof the colloidal particles having a small particle size and thecolloidal particles having an intermediate particle size, and the twopeaks shown in the colloidal particle size distribution represent thecolloidal particles having a small particle size and the colloidalparticles having an intermediate particle size.

Moreover, a PZT thin film obtained from the composition for PZT thinfilm formation comprising the colloidal solution as Sample 4 was densein film quality. This composition for PZT thin film formation could bestored for a long term of about 2 months under the ordinary temperature(2 or more months if stored at a low temperature).

According to the present invention, therefore, the colloidal solution,which is produced so as to have an average colloidal particle diameterof 1 to 100 nm and obtain two peaks in a colloidal particle sizedistribution, makes it possible to achieve a composition forferroelectric thin film formation, which can form a ferroelectric thinfilm dense in film quality, and which has excellent storage stability.

The ferroelectric thin film formed from the above composition forferroelectric thin film formation includes, for example, crystals of aferroelectric material (piezoelectric material) such as lead zirconatetitanate (PZT), or a relaxor ferroelectric having a metal, such asniobium, nickel, magnesium, bismuth or yttrium, added to such aferroelectric material. Examples of the composition therefor are PbTiO3(PT), PbZrO3 (PZ), Pb(ZrxTi1-x)O3 (PZT), Pb(Mg1/3Nb2/3)O3-PbTiO3(PMN-PT), Pb(Zn1/3Nb2/3)O3-PbTiO3 (PZN-PT), Pb(Ni1/3Nb2/3)O3-PbTiO3(PNN-PT), Pb(In1/2Nb1/2)O3-PbTiO3 (PIN-PT), Pb(Sc1/2Ta1/2)O3-PbTiO3(PST-PT), Pb(Sc1/2Nb1/2)O3-PbTiO3 (PSN-PT), BiScO3-PbTiO3 (BS-PT), andBiYbO3-PbTiO3 (BY-PT).

The ferroelectric thin film of the present invention, as describedabove, is formed from the composition for ferroelectric thin filmformation comprising the colloidal solution which has an averagecolloidal particle diameter of 1 to 100 nm and a particle sizedistribution having two or more peaks ascribed to such colloidalparticles. Since the resulting thin film is dense in film quality, itcan exhibit stable piezoelectric characteristics.

The above-described composition for ferroelectric thin film formationaccording to the present invention, and the ferroelectric thin filmformed using this composition for ferroelectric thin film formation canbe applied to the development of a wide variety of devices. Examples oftheir uses are, but not limited to, microactuators, filters,delay-lines, lead selectors, tuning-fork oscillators, tuning-forkclocks, transceivers, piezoelectric pickups, piezoelectric earphones,piezoelectric microphones, SAW filters, RF modulators, resonators, delaydevices, multistrip couplers, piezoelectric accelerometers, andpiezoelectric speakers.

Embodiment 2

An ink-jet recording head, an example of a liquid-jet head in which thepresent invention has been applied to a piezoelectric actuator, will bedescribed in detail with reference to FIGS. 3 and 4A, 4B. FIG. 3 is anexploded perspective view showing the outline of an ink-jet recordinghead, an example of a liquid-jet head. FIGS. 4A and 4B are,respectively, a plan view of the recording head in FIG. 3, and asectional view taken along line A-A′ in the plan view. As shown in FIG.3 and FIGS. 4A and 4B, a passage-forming substrate 10, in the presentembodiment, consists of a single crystal silicon substrate having aplane (110) of the plane orientation. An elastic film 50 comprisingsilicon dioxide (SiO2) and having a thickness of 0.5 to 2 μm, formedbeforehand by thermal oxidation, is present on one surface of thepassage-forming substrate 10.

In the passage-forming substrate 10, a plurality of pressure generatingchambers 12 partitioned by a plurality of compartment walls 11 arearranged parallel by anisotropic etching carried out on one surface sideof the single crystal silicon substrate. A communicating portion 13,which communicates with a reservoir portion 32 of a protective plate 30(to be described later), is formed outwardly of one end, in a direction(longitudinal direction) perpendicular to the direction of parallelarrangement (width direction) of the pressure generating chambers 12, ofthe pressure generating chamber 12. The communicating portion 13 andeach of the pressure generating chambers 12 are brought intocommunication via an ink supply path 14 at one end portion in thelongitudinal direction of each pressure generating chamber 12.

A mask film 51 used for formation of the pressure generating chambers 12is provided on the opening surface side of the passage-forming substrate10. Onto the mask film 51, a nozzle plate 20 having nozzle orifices 21bored therein is secured via an adhesive agent or a heat sealing film.The nozzle orifices 21 communicate with a zone near the end of thepressure generating chambers 12 on the side opposite to the liquidsupply paths 14.

An insulation film 55 having a thickness, for example, of about 0.4 μmis formed on the elastic film 50 placed on the side opposite to theopening surface of the passage-forming substrate 10. On the insulationfilm 55, a lower electrode film 60 with a thickness, for example, ofabout 0.2 μm, a ferroelectric thin film (piezoelectric layer) 70 with athickness, for example, of about 1.0 μm, and an upper electrode film 80with a thickness, for example, of about 0.05 μm are formed in alaminated state by a process (to be described later) to constitute apiezoelectric element 300. The ferroelectric thin film 70 in the presentembodiment has been formed by a composition for ferroelectric thin filmformation containing a colloidal solution which has an average colloidalparticle diameter, by the dynamic light scattering method, of 1 to 100nm, and which obtains a particle size distribution having two or morepeaks ascribed to such colloidal particles.

The piezoelectric element 300 refers to a portion including the lowerelectrode film 60, the ferroelectric thin film 70, and the upperelectrode film 80. Generally, one of the electrodes of the piezoelectricelement 300 is used as a common electrode, and the other electrode andthe ferroelectric thin film 70 are constructed for each pressuregenerating chamber 12 by patterning. A portion, which is composed of anyone of the electrodes and the ferroelectric thin film 70 that have beenpatterned, and which undergoes piezoelectric distortion upon applicationof voltage to both electrodes, is called a piezoelectric active portion.In the present embodiment, the lower electrode film 60 is used as thecommon electrode for the piezoelectric elements 300, while the upperelectrode film 80 is used as an individual electrode of eachpiezoelectric element 300. However, there is no harm in reversing theirusages for the convenience of the drive circuit or wiring. In eithercase, it follows that the piezoelectric active portion is formed foreach pressure generating chamber 12. Herein, the piezoelectric element300 and a vibration plate, where displacement occurs by a drive of thepiezoelectric element 300, are referred to collectively as apiezoelectric actuator. In the present embodiment, the elastic film 50,the insulation film 55, and the lower electrode film 60 act as thevibration plate.

The protective plate 30 is bonded via an adhesive agent onto a surfaceof the passage-forming substrate 10 where the piezoelectric elements 300have been formed. The protective plate 30 has, in a region opposed tothe piezoelectric elements 300, a piezoelectric element holding portion31 which can ensure a space enough wide not to impede movements of thepiezoelectric elements 300. Since the piezoelectric elements 300 areformed within the piezoelectric element holding portion 31, they areprotected in a state in which they are substantially free from theinfluence of an external environment. The space of the piezoelectricelement holding portion 31 may be, or need not be, sealed.

The protective plate 30 also has the reservoir portion 32 providedtherein, which constitutes at least a part of a reservoir 100 serving asa common ink chamber for the respective pressure generating chambers 12.The reservoir portion 32 is brought into communication with thecommunicating portion 13 of the passage-forming substrate 10, asdescribed above, to constitute the reservoir 100 serving as the commonink chamber for the respective pressure generating chambers 12. Athrough-hole 33, which penetrates the protective plate 30 in itsthickness direction, is provided in a region between the piezoelectricelement holding portion 31 and the reservoir portion 32 of theprotective substrate 30. A lead electrode 90 leading from eachpiezoelectric element 300 has a portion in the vicinity of its endexposed within the through-hole 33.

Furthermore, a compliance plate 40, which consists of a sealing film 41and a fixing plate 42, is bonded onto the protective plate 30. Thefixing plate 42 is formed from a hard material such as a metal. A regionof the fixing plate 42 opposed to the reservoir 100 defines an openingportion 43 completely deprived of the plate in the thickness direction.Thus, one surface of the reservoir 100 is sealed only with the sealingfilm 41 having flexibility.

With the ink-jet recording head of the present embodiment describedabove, ink is taken in from external ink supply means (not shown), andthe interior of the head ranging from the reservoir 100 to the nozzleorifices 21 is filled with the ink. Then, according to drive signalsfrom a drive IC (not shown), a drive voltage is applied between thelower electrode film 60 and the upper electrode film 80 corresponding toeach pressure generating chamber 12 to warp and deform the elastic film50, the insulation film 55, the lower electrode film 60, and theferroelectric thin film 70. As a result, the pressure inside eachpressure generating chamber 12 rises to eject ink droplets through thenozzle orifice 21.

In the above-described ink-jet recording head of the present embodiment,the ferroelectric thin film 70 is formed from the composition forferroelectric thin film formation having the properties of having anaverage colloidal particle diameter, by the dynamic light scatteringmethod, of 1 to 100 nm, and of obtaining a particle size distributionhaving two or more peaks ascribed to such colloidal particles. Thus, theferroelectric thin film 70 is dense in film quality. Accordingly, theink ejection characteristics of the head are stable, and the reliabilityof the head can be enhanced.

In the present embodiment, the ink-jet recording head for ejecting inkis taken for illustration as an example of the liquid-jet head. However,the present invention is not limited thereto. Examples of the liquid-jethead include recording heads for use in image recording devices such asprinters, color material jet heads for use in the production of colorfilters such as liquid crystal displays, electrode material jet headsfor use in the formation of electrodes for organic EL displays and FED(face emitting displays), and bio-organic material jet heads for use inthe production of biochips. It should be understood that such changes,substitutions and alterations can be made therein without departing fromthe spirit and scope of the invention as defined by the appended claims.

1. A method for producing a liquid-jet head which is equipped with apiezoelectric element having a ferroelectric thin film, as apiezoelectric actuator for jetting a liquid, comprising: coating acomposition for ferroelectric thin film formation; and drying and firingthe coated the composition for ferroelectric thin film formation,whereby the ferroelectric thin film is formed, wherein the compositionfor ferroelectric thin film formation comprises at least a colloidalsolution containing metals serving as materials for making theferroelectric thin film, said colloidal solution having an averagecolloidal particle diameter of 1 to 100 nm, and having a particle sizedistribution having two or more peaks, wherein the metals serving as thematerials for making the ferroelectric thin film include at least Pb, Zrand Ti, and the colloidal solution comprises each of (a), (b) and (c);(a) colloidal particles comprising lead acetate; (b) colloidal particlescomprising lead acetate and zirconium acetylacetonate stabilized bywater molecules; and (c) colloidal particles comprising titaniumalkoxides and lead acetate chelate-stabilized by amines.
 2. The methodfor producing the liquid-jet head according to claim 1, wherein theaverage colloidal particle diameter is 1 to 30 nm.
 3. The method forproducing the liquid-jet head according to claim 1, wherein the averagecolloidal particle diameter of the colloidal particles comprising leadacetate is 1 to 6 nm, the average colloidal particle diameter of thecolloidal particles comprising lead acetate and zirconiumacetylacetonate stabilized by water molecules is 1 to 10 nm, and theaverage colloidal particle diameter of the colloidal particlescomprising titanium alkoxides and lead acetate chelate-stabilized byamines is 3 to 50 nm.
 4. The method for producing the liquid-jet headaccording to claim 1, wherein the colloidal particles comprising leadacetate, the colloidal particles comprising lead acetate and zirconiumacetylacetonate stabilized by water molecules, and the colloidalparticles comprising titanium alkoxides and lead acetatechelate-stabilized by amines have the average colloidal particlediameter in increasing order.